Debugging in React Native Made Simple: Tools and Configuration Tips

Debugging in React Native can seem challenging at first, but with the right tools and a good setup, the process can be quite simple and efficient. In this post, I’ll show you how to set up VSCode to debug React Native, and introduce you to the best tools and packages to make your life easier.

1. Setting Up the Debug Environment in VSCode

Why Use VSCode?

Visual Studio Code (VSCode) is one of the most popular IDEs for React Native development due to its flexibility, extensions, and support for JavaScript/TypeScript. Moreover, it offers great integration with the debugging process.

Installing the Necessary Extensions

Before we begin, we need to install a few extensions in VSCode:

• React Native Tools: This extension offers complete support for debugging React Native directly in VSCode.
• ESLint: To ensure that your code is standardized and error-free.

How to install:

1. In VSCode, go to Extensions (square icon in the sidebar).
2. Search for “React Native Tools” and install the extension.
3. Repeat the process for the ESLint extension.

Configuring the Launch for Debugging

To debug React Native in VSCode, we need to configure launch.json. This allows you to use breakpoints and debug directly on your emulator or device.

1. In your project, go to the Run and Debug tab in VSCode (play icon).
2. Click Create a launch.json file and select React Native.
3. A launch.json file will be created. Here’s a basic setup:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug Android",
      "type": "reactnative",
      "request": "launch",
      "platform": "android",
      "sourceMaps": true,
      "outDir": "${workspaceFolder}/.vscode/.react",
      "enableDebug": true
    },
    {
      "name": "Debug iOS",
      "type": "reactnative",
      "request": "launch",
      "platform": "ios",
      "sourceMaps": true,
      "outDir": "${workspaceFolder}/.vscode/.react",
      "enableDebug": true
    }
  ]
}

With this setup, you can start debugging directly in VSCode by clicking Run and selecting either "Debug Android" or "Debug iOS."

2. Using Breakpoints in VSCode

Breakpoints are one of the most powerful ways to debug code, allowing you to pause execution at specific points and inspect variables and states.

How to Set Breakpoints:

1. In your React Native code, navigate to the line where you want to pause execution.
2. Click on the left sidebar (next to the line number) to set the breakpoint.
3. When you start debugging (with the emulator or device running), the code will automatically pause at the breakpoint, allowing you to inspect variable values and states.

Inspecting Variables and Components

When the code is paused at a breakpoint, you can check the value of variables in the Variables tab in the debugging panel. Additionally, you can add variables to the Watch section to monitor their changes throughout execution.

3. Using Chrome DevTools for Debugging

Chrome DevTools is a native tool that can be used for debugging React Native since React Native uses JavaScript for business logic.

How to Use Chrome DevTools:

1. Run the app in development mode (npx react-native run-android or npx react-native run-ios).
2. On your device or emulator, shake the device or press Cmd+D (iOS) or Cmd+M (Android) to open the developer menu.
3. Select Debug JS Remotely. This will open Chrome with DevTools connected to your React Native code.
4. In Chrome, you can inspect variables, use breakpoints, check logs, and more.

4. Essential Tools for Debugging in React Native

1. React Native Debugger

React Native Debugger is one of the most powerful tools for debugging. It combines Redux DevTools with Chrome DevTools and offers full support for state and action debugging.

How to Install:

• For macOS:

  brew install --cask react-native-debugger

• For Windows and Linux, download the latest version from the official GitHub repository.

Why Use It?

React Native Debugger provides a clear view of what's happening in your app, allowing you to inspect Redux state, dispatched actions, and any JavaScript errors.

2. Flipper

Flipper is an official Facebook tool that provides a complete debugging experience for React Native, iOS, and Android. It allows you to view logs, inspect layouts, visualize network requests, and more.

How to Use Flipper with React Native:

1. Install Flipper:

   • For macOS:

    brew install --cask flipper
   

• For Windows and Linux, download it from the official Flipper website.

1. In your React Native project, add Flipper:

   npm install --save-dev react-native-flipper

1. Run Flipper and open your app. It will automatically connect.

Why Use It?

Flipper is excellent for viewing real-time logs, inspecting your app’s layout, and monitoring network calls, making it one of the most comprehensive tools for debugging React Native apps.

5. Performance Debugging with Perf Monitor

Another important aspect of debugging is monitoring the performance of your app. For this, React Native offers a tool called Perf Monitor.

How to Use It:

1. On your device or emulator, shake the device or open the developer menu.
2. Select Show Perf Monitor.

This will display the frames per second (FPS) and other performance metrics for your app, helping you identify bottlenecks.

Conclusion

The debugging process in React Native can be simplified with the right tools and configurations. By using VSCode with the correct extensions, Chrome DevTools, React Native Debugger, and Flipper, you have a complete set of tools to quickly find and fix bugs. Set breakpoints, inspect variables, monitor performance, and adjust your workflow to debug more efficiently.

Remember: the key to effective debugging is understanding the tools and knowing how to apply them in your project. With these tips, you'll be ready to tackle any bug that comes your way!